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Health department declares the HIV epidemic over
-Bay Area Reporter, 2007
Public health officials now calling it an endemic
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The coming endemic

• Willi McFarland, MD, PhD
• Director of HIV Surveillance, San Francisco
  Department of Public Health

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Presentation

• What is epidemic?
• What is endemic?
• HIV epidemiology update for San Francisco
• Where are we?
• Where are we going?
• What do we do differently if there is a change
  from epidemic to endemic?

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Epidemic or Endemic?

• Endemic
• Epidemiological definitions
• Usual level of a disease in an area
• Constantly present in a locality, in a population
• Maintained in a population without the need for
  external inputs (imported or bridging from other
  populations)

• Epidemic
• Epidemiological definitions
• A disease occurring at a greater frequency than
  usually expected in a population, in a particular
  area
• Usually rapid rise, and subsequent fall
• Usually limited in time

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Lay connotations

• Epidemic
• Code Red
• Many infected at one time
• An outbreak
• Spreads wide and fast
• Very large, massive
• Very serious, high mortality, morbidity
• Crisis (but will eventually pass)
• Any cases of plague, cholera, ebola
• Any cases of a new, new disease
• Not usual in area, population

• Endemic
• Code Orange
• Native to the area
• Peculiar to the area
• Lyme disease in Lyme, Connecticut
• Confined to the population or area
• Always there
• Malaria in Africa
• Famine in Africa
• Crime in inner-cities

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An endemic

• Is not a good thing
• Is not cause for complacency
• Is not cause for fatalism
• Does not mean it is over

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What is neither epidemic nor endemic?

• A disease or infection that has been eradicated
  from a population or area
• Not sustained on its own
• Imported
• Sporadically bridged from other populations

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Definitions by HIV incidence
Gay men Epidemic
Second wave of epidemic
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Definition by HIV incidence
Gay men Epidemic
Injection drug users Endemic
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Definition by HIV incidence
Gay men Epidemic
Injection drug users Endemic
Heterosexuals Neither epidemic nor endemic
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Epidemiology of HIV in MSM in San Francisco
Where are we going?
Rise
Fall
Resurgence
Plateau/Down
?
Nadir
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New HIV infections, San Francisco
2001 Consensus Estimates
2006 Consensus Estimates
Rise
Fall
Resurgence
Plateau/down
Nadir
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San Francisco HIV/AIDS, 2006
Tenderloin
Castro

• Cum. AIDS cases 27,027
• AIDS deaths 18,232
• ART gt91 of AIDS cases
• MSM 90
• Living with HIV 18,708
• New infections 977 this year

In 2007 750,000 inhab.
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Recall Previous Trends in Indicators, MSM 1995 to
2001
UP
LEVEL
DOWN

• MSM living with AIDS
• STI in MSM with AIDS
• Unprotected sex in MSM
• Rectal gonorrhea among MSM
• Primary and secondary syphilis among MSM
• Number of sex partners in MSM with STI
• Incidence of HIV in a cohort of MSM
• Incidence of HIV among MSM at VCT
• Incidence of HIV in MSM by STARHS of VCT data

(Nothing)
(Nothing)
Interpretation in 2001 Rise in HIV
incidence Second wave of the epidemic
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HIV in San Francisco, where are we?
Resurgent epidemic scenario
Rise
Fall
Continued trend
Resurgence
Nadir
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HIV incidence indicators, MSM2001 - 2006
UP
LEVEL
DOWN

• Repeat tester incidence
• CTRPN cases
• New HIV/AIDS cases

• STARHS AHP
• STARHS CC
• Incidence BSS
• Discordant UAI HIV
• Discordant UAI HIV-
• Syphilis
• Unknown HIV

• Rectal GC
• AIDS with STD
• No. of partners

Interpretation in 2006 Modest decrease in HIV
incidence Reversal of the second wave of the
epidemic
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Epidemiology of HIV in MSM in San Francisco
Where are we going?
Rise
Fall
Resurgence
Plateau/Down
?
Nadir
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Endemic fear
Epidemic Rapid rise (and fall)
Second wave of the epidemic More susceptibles,
more risk behavior
Endemic Approximately the same number of new
infections indefinitely
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HIV incidence indicators, MSM2001 - 2006
UP
LEVEL
DOWN

• Repeat tester incidence
• CTRPN cases
• New HIV/AIDS cases

• STARHS AHP
• STARHS CC
• Incidence BSS
• Discordant UAI HIV
• Discordant UAI HIV-
• Syphilis
• Unknown HIV

• Rectal GC
• AIDS with STD
• No. of partners

Interpretation in 2006 Modest decrease in HIV
incidence Reversal of the second wave of the
epidemic
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HIV incidence indicators, MSM2001 - 2007
UP
LEVEL
DOWN

• AIDS with STD
• Multiple partners

• Incidence BSS
• Unknown HIV status

• Repeat tester HIV incidence
• CTRPN cases
• New HIV/AIDS cases
• STARHS AHP
• STARHS CC
• Rectal gonorrhea
• Syphilis
• Discordant UAI HIV
• Discordant UAI HIV-

Interpretation in 2007 Endemic
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Male rectal gonorrhea
Secondary
Early latent
Primary
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Male rectal gonorrhea
Male rectal gonorrhea
Male gonoccocal proctitis
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HIV incidence among MSM
HIV Incidence ()
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Sexual risk behavior among MSM
Unprotected anal sex
Serodiscordant UAI, HIV
Potentially serodiscordant UAI, HIV-
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What would Willi say now?

• Down, level, up, down, level
• Technically, the evidence points to an endemic.
• Does this make a sound bite?
• I hope that HIV will be NEITHER epidemic nor
  endemic in San Francisco. But, unless we act more
  effectively, we can expected nearly 1000
  infections every year for many years to come.
• HIV is hyper-endemic in MSM in San Francisco
  Jeff Klausner

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Why an endemic is not a good thing

• The burden of HIV disease in San Francisco
  remains enormous
• It is not endemic for everyone
• Sum of all chains of transmission in networks
• New risk factors, new epidemics within endemic
• Disparities
• Can still be prevented
• HIV will be sustained in San Francisco
  indefinitely
• HIV prevalence will rise, even if incidence is
  stable due to survival
• Relentless inevitability of infection over time

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Relentless inevitability in a cohort of 20
year-old MSM HIV Incidence 1.9
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African-American 20 year-old MSM Cohort HIV
Incidence 4.0
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It doesnt have to be that way
Epidemic
Second wave
Eradication
Imported, bridged, sporadic
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Prevention implications

• What do we do differently if there is a change
  from epidemic to endemic?

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WWWD?

• I dont know

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Prevention implications

• Epidemics in general
• Rapid case detection
• Notify the public
• Treat individuals
• Treat contacts (PEP, PREP)
• Deputize health personnel
• Commandeer resources
• Quarantine populations
• Stay indoors
• Isolate individuals
• Isolate contacts
• Kill ground squirrels, rats, mice, snails, deer
• Only a few of the above relevant to HIV

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Prevention implications

• Endemics in general
• Improve vaccination
• Improve existing vaccination programs
• Invent new vaccines
• Structural interventions
• To water supply
• Drain swamps, clear brush, prevent rodent and
  other vector population growth
• Infrastructure improvements to care for infected
• Prophylaxis (malaria) for temporary exposure
• Eradication, end game

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Prevention implications of epidemic HIV

• Principles
• Intervene as soon as possible
• High surveillance vigilance
• Target highest risk populations
• Scale up what works as fast as possible
• Identify and address specific drivers of
  transmission

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Prevention implications of endemic HIV

• Principles
• Evaluate to see what works
• Continue what works, improve what works
• Structural interventions
• For HIV prevention?
• Circumcision for heterosexual transmission
• Strengthen infrastructures for the long-term
• Early detection and treat as much HIV when and as
  needed
• Educate next generation of susceptibles
• Drug treatment, harm reduction
• STD control
• Identify and address specific drivers of
  continuing transmission
• Epidemics within endemic
• Long-term behavior change (?)
• Vaccine (?)
• Research

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It doesnt have to be that way
Epidemic
Second wave
Eradication
Imported, bridged, sporadic